static const float4 palette[16] = {
    float4(0x00 * 255 / 63, 0x00 * 255 / 63, 0x00 * 255 / 63, 0xff) / 0xff,
    float4(0x00 * 255 / 63, 0x00 * 255 / 63, 0x2f * 255 / 63, 0xff) / 0xff,
    float4(0x00 * 255 / 63, 0x2f * 255 / 63, 0x00 * 255 / 63, 0xff) / 0xff,
    float4(0x00 * 255 / 63, 0x2f * 255 / 63, 0x2f * 255 / 63, 0xff) / 0xff,
    float4(0x2f * 255 / 63, 0x00 * 255 / 63, 0x00 * 255 / 63, 0xff) / 0xff,
    float4(0x2f * 255 / 63, 0x00 * 255 / 63, 0x2f * 255 / 63, 0xff) / 0xff,
    float4(0x30 * 255 / 63, 0x1f * 255 / 63, 0x00 * 255 / 63, 0xff) / 0xff,
    float4(0x2f * 255 / 63, 0x2f * 255 / 63, 0x2f * 255 / 63, 0xff) / 0xff,
    float4(0x1f * 255 / 63, 0x1f * 255 / 63, 0x1f * 255 / 63, 0xff) / 0xff,
    float4(0x00 * 255 / 63, 0x00 * 255 / 63, 0x3f * 255 / 63, 0xff) / 0xff,
    float4(0x00 * 255 / 63, 0x3f * 255 / 63, 0x00 * 255 / 63, 0xff) / 0xff,
    float4(0x00 * 255 / 63, 0x3f * 255 / 63, 0x3f * 255 / 63, 0xff) / 0xff,
    float4(0x3f * 255 / 63, 0x00 * 255 / 63, 0x00 * 255 / 63, 0xff) / 0xff,
    float4(0x3f * 255 / 63, 0x00 * 255 / 63, 0x3f * 255 / 63, 0xff) / 0xff,
    float4(0x3f * 255 / 63, 0x3f * 255 / 63, 0x00 * 255 / 63, 0xff) / 0xff,
    float4(0x3f * 255 / 63, 0x3f * 255 / 63, 0x3f * 255 / 63, 0xff) / 0xff,
};
